Highways England is advising motorists to plan their journeys between the South West and London ahead of next week’s Summer Solstice event at Stonehenge as the A303 is set to be gridlocked.

Up to 25,000 people are expected to visit Stonehenge on Thursday, 20 June and the morning of Friday, 21 June, and with limited parking on site, English Heritage is once again urging visitors to use public transport or car share.

Two grass car parks will be accessible from the A303 from 7pm on 20 June until 6am on 21 June, and once full, visitors will not be allowed onto the site. The car parks will be vacated by noon on the Friday.

Bus transport will be available from Salisbury train station and pedestrians are also advised to use the designated, temporary pedestrian crossing on the A303 at Stonehenge Cottages

Highways England’s A303 Amesbury to Berwick Down project team is currently conducting ground investigation surveys along the proposed route past Stonehenge and this work will be respectfully halted for the Summer Solstice.

The programme of work, involving borehole and trial pit investigations to inform the scheme’s later procurement process, will be paused on the Thursday, in advance of the Solstice event, and will restart on Monday, 24 June and conclude later in the summer.

During the Solstice event, Highways England will assist the flow of traffic both before and after the event. A 40mph speed limit will be in place on the A303 between the Countess roundabout and Longbarrow roundabout, with the lay-bys closed in between, and the dual carriageway will be reduced to a single lane between Countess Roundabout and Stonehenge Cottages.

Gareth Price, Highways England emergency planning officer for the south west, said: “We are anticipating traffic volumes to increase around the event, and our aim is to keep the Highways England network running while keeping road users safe and informed.

“The traffic management will be in place for safety and to keep disruption to a minimum, and we advise all road users to check our traffic and travel information channels, plan their journeys and allow plenty of time.

“A temporary pedestrian crossing will also be installed near Stonehenge Cottages for the safety of visitors walking from Stonehenge Road, Amesbury, and we advise all pedestrians to use this to access the site.”